*{
    margin:0;
    padding:0;
}
.box{
    position: relative;
    width:600px;
    height:240px;
    border:4px solid red;
    margin:50px auto;
}
.box span{
    position: absolute;
    top:90px;
    display: block;
    width:30px;
    height:60px;
    background-color: aliceblue;
    text-align: center;
    line-height: 60px;
    cursor: pointer;
    user-select: none;
}
.box span.right{
    right:0px;
}

.box img{
    width:100%;
    height:100%;
}